SELECT Statements

A SELECT statement can consist of the following basic clauses.

SELECT
INTO
FROM
JOIN
WHERE
GROUP BY
HAVING
UNION
ORDER BY
LIMIT

SELECT Syntax

The following syntax diagram outlines the syntax supported by the ADLS adapter:

SELECT {
  [ TOP <numeric_literal> | DISTINCT ]
  { 
    * 
    | { 
        <expression> [ [ AS ] <column_reference> ] 
        | { <table_name> | <correlation_name> } .* 
      } [ , ... ] 
  }
  [ INTO csv:// [ filename= ] <file_path> [ ;delimiter=tab ] ]
  { 
    FROM <table_reference> [ [ AS ] <identifier> ] 
  } [ , ... ]
  [ 
    JOIN <table_reference> [ ON <search_condition> ] [ [ AS ] <identifier> ] 
  ] [ ... ] 
  [ WHERE <search_condition> ]
  [ GROUP BY <column_reference> [ , ... ]
  [ HAVING <search_condition> ]
  [ UNION  [ ALL ] <select_statement> ]
  [ 
    ORDER BY 
    <column_reference> [ ASC | DESC ] [ NULLS FIRST | NULLS LAST ]
  ]
  [
    LIMIT <expression>
    [ 
      { OFFSET | , }
      <expression> 
    ]
  ] 
}

  <expression> ::=
    | <column_reference>
    | @ <parameter> 
    | ?
    | COUNT( * | { [ DISTINCT ] <expression> } )
    | { AVG | MAX | MIN | SUM | COUNT } ( <expression> ) 
    | NULLIF ( <expression> , <expression> ) 
    | COALESCE ( <expression> , ... ) 
    | CASE <expression>
        WHEN { <expression> | <search_condition> } THEN { <expression> | NULL } [ ... ]
    [ ELSE { <expression> | NULL } ]
      END 
    | <literal>
    | <sql_function> 

  <search_condition> ::= 
    {
      <expression> {  } [ <expression> ]
    } [ { AND | OR } ... ]

Examples

Return all columns:
```
SELECT * FROM Resources
```

Rename a column:

SELECT "Permission" AS MY_Permission FROM Resources

Cast a column's data as a different data type:

SELECT CAST(AnnualRevenue AS VARCHAR) AS Str_AnnualRevenue FROM Resources

Search data:

SELECT * FROM Resources WHERE Type = 'FILE'

The ADLS APIs support the following operators in the WHERE clause: .
```
SELECT * FROM Resources WHERE Type = 'FILE';
```
Return the number of items matching the query criteria:
```
SELECT COUNT(*) AS MyCount FROM Resources 
```
Return the number of unique items matching the query criteria:
```
SELECT COUNT(DISTINCT Permission) FROM Resources 
```
Return the unique items matching the query criteria:
```
SELECT DISTINCT Permission FROM Resources 
```

Sort a result set in ascending order:

SELECT FullPath, Permission FROM Resources  ORDER BY Permission ASC

Aggregate Functions

For SELECT examples using aggregate functions, see Aggregate Functions.

JOIN Queries

See JOIN Queries for SELECT query examples using JOINs.

Date Literal Functions

Date Literal Functions contains SELECT examples with date literal functions.

Window Functions

See Window Functions for SELECT examples containing window functions.

Table-Valued Functions

See Table-Valued Functions for SELECT examples with table-valued functions.

TDV Adapter for Azure Data Lake Storage